Ultrasonic testing equipment is used in a variety of applications such as for measuring flow, determining flaws, measuring thickness, and gauging corrosion. This equipment is used with a variety of materials such as metals, plastics, glass, and chemicals. One particular type of ultrasonic testing apparatus is a pulser-receiver. Pulser-receivers are used for a variety of non-destructive testing applications, including flaw detection and thickness gauging. Some pulser-receivers operate at lower frequencies, such as ½ MHz to 25 MHz. Certain applications require high frequency pulsers-receivers operating at about 100 MHz.
Pulser-receivers are available, for example, from GE-Panametrics, 221 Crescent Street, Waltham, Mass. 02453-3497 USA, such as model number 5058PR, a high voltage pulser-receiver for ultrasonic test and measurement applications requiring a high material penetration capability; model 5072PR, an ultrasonic pulser-receiver configured to provide high energy, high gain performance for low frequency investigation of attenuating materials; model 5073PR, a broadband 75 MHz ultrasonic pulser-receiver which provides flaw detection capabilities for very high frequency, high resolution ultrasonic testing when used with an oscilloscope and appropriate transducers, model 5077PR, an ultrasonic pulser-receiver for providing high voltage square wave performance over a wide range of applications, model 5800PR, a computer-controlled pulser-receiver for general purpose ultrasonic testing using computer-based systems for automatic testing, or stored setups to speed repetitive manual tasks, and model 5900PR, a computer-controlled pulser-receiver for high frequency ultrasonic testing using computer-based systems for automatic testing, or stored setups to speed repetitive manual tasks.
Pulser-receivers are also available from JSR Ultrasonics, A Division of Imagilent, 3800 Monroe Avenue, Pittsford, N.Y. 14534 USA, such as model DPR500, which is a dual channel instrument having two pulser-receivers integrated into one unit, and model DPR300, which is a computer controlled ultrasonic pulser-receiver with a low noise receiver.
For some pulser-receivers, replacement transducers are no longer available. Transducers sometimes fail and require replacement. In some applications, there will be multiple failures per year. The cost of replacement can be, for example, about $10,000 to $16,000. Transducer costs vary based on fabrication yields and availability of parts.
Another problem with existing transducers is that they are physically large, heavy and focused. These attributes require, in some applications, that transducers be servoed to track the front surface of a sample under inspection. To add a servo sub-system to each of the transducers of a system could be very costly.
It would be desirable to have, in some embodiments, lower cost pulser-receivers including lower cost transducers. It would also be desirable to avoid the added cost of the transducer servomechanisms, in some embodiments.
Additionally, the time required for general maintenance (i.e. to replace a failed transducer, align the system, and calibrate the existing transducers) is, for example, 20 to 28 man-days. It would be desirable to provide pulser-receivers, in some embodiments, for which the transducers can be removed and replaced, and the system aligned and calibrated, more quickly.
In computer-controlled pulser-receivers, a computer will typically send a trigger to a pulser-receiver. The pulser-receiver sends out a high voltage pulse in response to the trigger. A piezoelectric transducer converts electrical energy to mechanical energy and sends out a pulse. When the pulse hits a certain material, such as at an interface of different types of materials, a reflection or echo comes back. There will usually be some ringing.
It would desirable to have pulser-receivers with quick recovery times, in some embodiments.